The present invention relates to a mechanism which facilitates installation of a steering wheel assembly onto a steering column assembly while making the necessary electrical connections between the steering wheel assembly and the vehicle electrical system.
Prior to the introduction of modular steering wheels, also known as wheel air bags, steering wheel assemblies could be attached to the steering shaft in a straightforward manner. Installation of the steering wheel assembly onto the steering shaft was made while viewing the shaft through the hub of the steering wheel from the front face (driver's side) and guiding the steering wheel into place. A nut or bolt was then affixed to the top of the shaft, using the available access through the front face of the steering wheel, and was tightened to pull the steering wheel assembly into its proper functional position. At this point the driver's air bag module was loaded into the open face of the wheel, covering the hub area, and was held in place using fasteners driven through the wheel armature from the back side of the steering wheel assembly.
In order to reduce assembly time and labor cost and to improve the Class A surface appearance, a modular wheel was developed. The modular wheel comprises a steering wheel assembly molded such that the air bag cover and steering wheel Class A surface are molded as one, an air bag module loaded into this molded assembly from the rear or bottom, a hub plate with attachment points to the molded assembly and the steering shaft, and attachment hardware, generally embedded in the hub plate. This assembly is such that the former attachment method is no longer valid. The wheel and air bag module are installed as one unit and there is no longer access to the steering shaft through the face of the steering wheel assembly. This makes it somewhat more difficult to mate up the hub of the steering wheel with the steering shaft.
It should be noted that during steering wheel assembly various electrical connections must be made between the steering wheel and the vehicle electrical system to power the horn, air bag inflator, and, frequently, additional accessories. These connections are generally made by plugging one or more pigtail connectors located on the steering column into complimentary mating pigtail connectors on the steering wheel assembly. There is always the danger that one or more of these pigtail leads may be damaged during installation and this danger may be exacerbated during blind assembly.